In the art of machine tools with tool beds and specifically in the art of machine clamps, it has long been desirable to use various types of clamps to hold down a work piece on the tool bed.
This is primarily for the reason that the work pieces must be tightly secured to the bed so that precise operations may be conducted on said work piece without fear of movement after the operation has been calibrated.
There have been a number of solutions to this problem of securing work pieces by use of various types of clamps.
Exemplary of such devices are the clamps disclosed in the following patents:
U.S. Pat. No. 928,657 Howell 1909 PA1 U.S. Pat. No. 2,639,744 Herbert 1953 PA1 U.S. Pat. No. 2,913,965 Collis 1959 PA1 U.S. Pat. No. 3,210,069 Holtz 1965 PA1 U.S. Pat. No. 3,227,438 Sequin 1966 PA1 U.S. Pat. No. 2,994,236 McCormick PA1 U.S. Pat. No. 2,803,277 Gamura PA1 U.S. Pat. No. 2,487,022 LaPlaca 1949 PA1 U.S. Pat. No. 2,577,029 Moorehead 1951 PA1 U.S. Pat. No. 3,380,730 Carver 1968 PA1 U.S. Pat. No. 3,712,606 Cole 1973
Other patents have also disclosed threaded adjustable fulcrums such as the following patents:
In each of these patents, it has been taught that the elongated clamp body, should have the thrust screw in the center and the pivot, or fulcrum at one end.
The devices of the above patents have the disadvantage of being multiple piece units which take a great deal of time to be installed to the bed plate and secured to the work piece.